Iridium flare predictions added to the GSOC Web site

Chris Peat (
Thu, 18 Dec 1997 18:14:50 +0100

As promised in my recent announcement of the new satellite predictions on
the German Space Operations Centre (GSOC) web site, we have now added a page
giving dynamic predictions of Iridium flares for the next 5 days.

If you have already bookmarked the home page, all you have to do is reload
the page and you should see the new link. If not, the starting page URL is
(as before);

Please be patient when generating the predictions - it can take 20 seconds
or so just for the calculations.

The software is a new development and does not use any of the existing
programs available on the Internet. I have compared the accuracy with the
results produced by Rob Matson's program and they seem to be accurate.

Since my last mail, many people have asked which satellites are in the
database, and it appears that many important ones were missing. The original
database used the 140 or so satellites in Jay Respler's "100 or so brightest
satellites" list. I have now greatly expanded the database by using Ted
Molczan's list of 1200 or so objects, and you will notice that the
predictions take significantly longer to produce. Many of these objects are
never visible to the naked eye, but the software automatically selects the
brightest ones as input to the prediction software. Classified satellites,
such as Lacrosse, are now included. You will also notice that there are now
three options for calculating the visible passes of all satellites according
to magnitude - 3.5, 4.0 and 4.5, and these pages take between 10 and 30
seconds to compute. In the new year, all the pages should load faster when
we install a new, faster server.

In January, we also intend to add a set of pages offering various listings
of the satellites in our database, which is also something several people
have requested.

Comments and suggestions are welcome.


Chris Peat

Chris Peat, Anite Systems
Currently working at the German Space Operations Centre near Munich